Exercise may Reduce DNA Damage caused by Chronic and Traumatic Stress
Scientists at the University of California, San Francisco (UCSF) have recently reported multiple studies that reveal psychological stress leads to shorter telomeres, or DNA damage. Telomeres are caps located on the ends of chromosomes (DNA strands inside cell nuclei which dictate genetic characteristics) that protect and stabilize genetic data while serving as a measure of cellular age and health. Each time a cell divides a fraction of the telomeres drop off; after a specific number of cellular divisions the telomeres reach a critical length and the cell normally dies. Recently, scientists have discovered that shorter telomeres are linked with a broad range of aging-related diseases and indicate elevated risk of cardiovascular disease and a variety of cancers. The recent UCSF study findings suggest that exercise may prevent this damage and increased risk of disease by reducing telomere erosion.
In these novel studies presented at the 2011 American Association for Cancer Research (AACR) Annual Meeting, telomeres were examined in white blood cells of the immune system, which protects the body against infectious agents and cellular damage. As stated by co-author Jue Lin, PhD, “Our findings suggest that traumatic and chronic stressful life events are associated with shortening of telomeres in cells of the immune system, but that physical activity may moderate this impact.” A previous 2004 study at UCSF set the groundwork for the current studies as the research team found that the perception of psychological stress in female caregivers of chronically sick children was related to shorter telomeres in lymphocytes. This finding provided evidence that telomere preservation potentially mediates the negative effects of stress on health.
In the current research:
- One study examined 63 healthy post-menopausal women who were primary caregivers for a family member with dementia. An increased perception of stress was related to an increase in the odds of having short telomeres – but only in the non-exercising women. Among the exercising women, perceived stress was not related to shortened telomere length.
- A second study examined 43 individuals ages 20 to 50 with chronic post-traumatic stress disorder (PTSD). They were compared to 47 age and sex-matched participants without PTSD. The results clearly revealed a relationship between PTSD and short telomere length; specifically, the individuals who were exposed to traumatic experiences during childhood (at or before age 14) were primarily responsible for the statistical correlation.
- A third study analyzed data from 251 healthy, non-smoking women ages 50 to 65 who engaged in varying levels of activity. The findings showed that non-exercising women with histories of childhood abuse had shorter telomeres than those with no histories of abuse. Conversely, among those women who exercised regularly, no link was seen between childhood abuse and telomere length; after controlling for body mass index, income, education and age.
Overall the research displayed a clear relationship between extreme stress and negative effects on the immune system; specifically telomere erosion. It seems that traumatic experiences during the formative years and adolescence have a significant effect on stress-related DNA damage. On the positive side, all of the studies showed that regular exercise reduces telomere damage and the potential for premature cellular death. Most people recognize that physical activity can be a viable method for stress management, but up until recently it was not fully understood to what significant physiological extent this general knowledge stands true. Physical activity not only promotes hormonal actions that combat the acute effects of distress, but also can expand the lifespan of specific structures that have a significant influence on lifespan.
